Breathing assistance apparatus

ABSTRACT

A improved interface is disclosed for delivering CPAP therapy to patients. The interface has a sliding engagement to the headgear. The sliding engagement allows substantial relative lateral movement eg: when face is distorted from sleeping on side, while still providing adequate compressive force to avoid side leakage. The sliding engagement also allows easy release from the headgear.

FIELD OF INVENTION

[0001] This invention relates to delivery of respiratory gasesparticularly though not solely to patient interfaces for providing gasesto patients requiring respiratory therapy.

BACKGROUND OF THE INVENTION

[0002] In the art of respiration devices, there are well known a varietyof respiratory masks which cover the nose and/or mouth of a human userin order to provide a continuous seal around the nasal and/or oral areasof the face such that gas may be provided at positive pressure withinthe mask for consumption by the user. The uses for such masks range fromhigh altitude breathing (i.e., aviation applications) to mining and firefighting applications, to various medical diagnostic and therapeuticapplications.

[0003] One requisite of such respiratory masks has been that theyprovide an effective seal against the user's face to prevent leakage ofthe gas being supplied. Commonly, in prior mask configurations, a goodmask-to-face seal has been attained in many instances only withconsiderable discomfort for the user. This problem is most crucial inthose applications, especially medical applications, which require theuser to wear such a mask continuously for hours or perhaps even days. Insuch situations, the user will not tolerate the mask for long durationsand optimum therapeutic or diagnostic objectives thus will not beachieved, or will be achieved with great difficulty and considerableuser discomfort.

[0004] In common with prior art designs, is an inability to sealeffectively when the user's face becomes distorted. For example, asshown in the prior art mask of FIG. 1 when the user 300 is sleeping onhis or her side, one side 302 of the headgear tends to be pulled tightwhile the other side 304 tends to be loose. This causes the axis of themask 306 to be twisted with respect to the axis of the head 308—due tothe net torque from the headgear—resulting in leakage 310 on one side.The user 300 sleeping on his or her side may also distort the facialcontours around the nasal area 312 and may lead to further leakage.

SUMMARY OF INVENTION

[0005] It is an object of the present invention to provide a nasal maskwhich goes some way to overcoming the abovementioned disadvantages inthe prior art or which will at least provide the industry with a usefulchoice.

[0006] Accordingly in one aspect the invention consists in a device fordelivering a supply of gases to a user comprising or including:

[0007] a patient interface, in use in fluid communication with saidsupply of gases,

[0008] securement means attached to or around the head of said user, and

[0009] engaging means adapted to slidingly engage said securement meanswith said patient interface.

[0010] In a second aspect the present invention consists in nasal markfor delivering gases to a user comprising or including:

[0011] a body portion having a inlet, in use said inlet receiving asupply of gases,

[0012] sealing means engaged with said body portion, and adapted to sealagainst the facial contours of said user, and

[0013] engaging means adapted to in use provide a sliding engagementwith a means of securement to a user, and a compressive force on saidsealing means to ensure said supply of gases is delivered to a userwithout significant leakage.

[0014] In a third aspect the present invention consists in a CPAP systemfor delivering gases to a user comprising or including a pressurisedsource of gases, transport means in fluid communication with saidpressurised source adapted to convey said gases, and a patient interfacein fluid communication with said transport means in use delivering saidgases to said user, the improvement comprising that said patientinterface adapted to sliding engage with a means of securement to auser, to ensure said supply of gases is delivered to a user withoutsignificant leakage.

[0015] To those skilled in the art to which the invention relates, manychanges in construction and widely differing embodiments andapplications of the invention will suggest themselves without departingfrom the scope of the invention as defined in the appended claims. Thedisclosures and the descriptions herein are purely illustrative and arenot intended to be in any sense limiting.

[0016] The invention consists in the foregoing and also envisagesconstructions of which the following gives examples.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One preferred form of the present invention will now be describedwith reference to the accompanying drawings in which;

[0018]FIG. 1 is a plan view of a prior art mask illustrating side leak,

[0019]FIG. 2 is a plan view of a mask according to the preferredembodiment of the present invention,

[0020]FIG. 3 is a block diagram of a humidified continuous positiveairway pressure (CPAP system) as might be used in conjunction with thepresent invention,

[0021]FIG. 4 is an illustration of the mask in use according to thepreferred embodiment of the present invention,

[0022]FIG. 5 is a front view of the mask illustrating the headgearsecurement to the mask,

[0023]FIG. 6 is a perspective view of the mask showing multiple engagingclips,

[0024]FIG. 7 is a perspective view of the mask showing the sliding strapclipped in place,

[0025]FIG. 8 is a side view of the sliding strap,

[0026]FIG. 9 is a perspective view of the cannula with the sliding strap

[0027]FIG. 10 is a side view of the cannula in use on a neonate,

[0028]FIG. 11 is a perspective view of the fill face mask with slidingloop,

[0029]FIG. 12 is a front view of the full face mask with sliding loop,

[0030]FIG. 13 is a top view of the full face mask with sliding loop,

[0031]FIG. 14 is a front view of the single sliding strap on themouthpiece,

[0032]FIG. 15 is a perspective view of the single sliding strap on themouthpiece,

[0033]FIG. 16 is a side view of the single sliding strap on themouthpiece,

[0034]FIG. 17 is a front view of the double sliding strap on themouthpiece, and

[0035]FIG. 18 is a perspective view of the sliding strap for the fullface mask.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] The present invention provides improvements in the field ofpatient interfaces for use in respiratory therapy. In particular aninterface is described which is more comfortable for the user to wearand reduces the side leakage as compared with interfaces of the priorart. It will be appreciated that while a mask is described in thepreferred embodiment, the present invention can be used in respiratorycare generally or with a ventilator but will now be described below withreference to use in a humidified CPAP system. It will be appreciated thepresent invention could equally be used with any form of positivepressure respiratory therapy.

[0037] With reference to FIG. 3 a humidified Continuous Positive AirwayPressure to (CPAP) system is shown in which a patient 1 is receivinghumidified and pressurised gases through a nasal mask 2 connected to ahumidified gases transportation pathway or inspiratory conduit 3. Itshould be understood that delivery systems could also be VPAP (VariablePositive Airway Pressure) and BiPAP (Bi-level Positive Airway Pressure)or numerous other forms of respiratory therapy. Inspiratory conduit 3 isconnected to the outlet 4 of a humidification chamber 5 which contra avolume of water 6. Inspiratory conduit 3 may contain heating means orheater wires (not shown) which heat the walls of the conduit to reducecondensation of humidified gases within the conduit. Humidificationchamber 6 is preferably formed from a plastics material and may have ahighly heat conductive base (for example an aluminium base) which is indirect contact with a heater plate 7 of humidifier 8. Humidifier 8 isprovided with control means or electronic controller 9 which maycomprise a microprocessor based controller executing computer softwarecommands stored in associated memory.

[0038] Controller 9 receives input from sources such as user input meansor dial 10 through which a user of the device may, for example, set apredetermined required value (preset value) of humidity or temperatureof the gases supplied to patient 1. The controller may also receiveinput from other sources, for example temperature and/or flow velocitysensors 11 and 12 through connector 13 and heater plate temperaturesensor 14. In response to the user set humidity or temperature valueinput via dial 10 and the other inputs, controller 9 determines when (orto what level) to energise heater plate 7 to heat the water 6 withinhumidification chamber 5. As the volume of water 6 within humidificationchamber 5 is heated, water vapour begins to fill the volume of thechamber above the water's surface and is passed out of thehumidification chamber 5 outlet 4 with the flow of gases (for exampleair) provided from a gases supply means or blower 15 which enters thechamber through inlet 16. Exhaled gases from the patient's mouth arepassed directly to ambient surroundings in FIG. 3.

[0039] Blower 15 is provided with variable pressure regulating means orvariable speed fan 21 which draws air or other gases through blowerinlet 17. The speed of variable speed fan 21 is controlled by electroniccontroller 18 (or alternatively the function of controller 18 couldcarried out by controller 9) in response to inputs from controller 9 anda user set predetermined required value (preset value) of pressure orfan speed via dial 19.

[0040] Nasal Mask

[0041] Referring to FIG. 4 the nasal mask, according to the preferredembodiment of the present invention, is shown in detail. The maskincludes a hollow body 102 with an inlet 103 connected to theinspiratory conduit 3. The mask 2 is positioned around the nose of theuser 1 with the headgear 108 secured around the back of the head of thepatient 1. The restraining force from the headgear 108 on the hollowbody 102 and the forehead rest 106 ensures enough compressive force onthe mask cushion 104, to provide an effective seal against the patient'sface.

[0042] The hollow body 102 is constructed of a relatively inflexiblematerial for example, polycarbonate plastic. Such a material wouldprovide the requisite rigidity as well as being transparent and arelatively good insulator. The expiratory gases can be expelled througha valve (not shown) in the mask, a further expiratory conduit (notshown), or any other such method as is known in the art

[0043] Mask Headgear

[0044] Referring now to FIGS. 4 and 5 the headgear 108 is shownconnected to the hollow body 102. Rather than traditional fixed oradjustable attachments the present invention utilises a slidingengagement between the headgear 108 and the hollow body 102. This isachieved in one embodiment with a loop 120, running through harnessingclips 122, 124 on either side of the headgear 108 and over the top ofthe hollow body 102. The loop 120 is reciprocally engaged with guides126, 128 mounted on the top surface of the hollow body 102. The guidesconstrain the loop 120 but allow it to slide in and out, meaning theheadgear 108 can move laterally, independently of the hollow body 102.

[0045] The advantage to this is as the face is contorted during varioussleeping positions the headgear is able to move with the changes inposition while the mask is left in the correct position on the nose ofthe user and an effective seal is maintained.

[0046] Additional guides 129, 130, 131 allow the user to adjust positionof loop 120, giving ability to get different pressure on the sealdepending on loop 120 position.

[0047] To further ensure user comfort and effective pressure on the maskcushion 104, the headgear 108 may be constructed either using two strapsrunning around the back of the user's head as shown in FIG. 4 or with apartial skull cap or any other configurations as are known in the art.In this case the straps or partial skull cap would be constructed usingneoprene but may also be constructed using any material as is known inthe art which will be comfortable for the user.

[0048] In a further embodiment shown in FIGS. 6, 7 and 8 the presentinvention is illustrated using a sliding strap to attach the headgear108 to the hollow body 102. The strap 200, shown in FIG. 8 in isolation,is constructed of polyacetal (Delrin 500P NC010) using injectionmoulding techniques to give a polished finish. This material, similar toother nylon based derivatives, with its polished finish has aparticularly low friction co-efficient, and therefore slides withrespect to the hollow body 102 with very little resistance.

[0049] As shown in FIG. 6, the hollow body 102 includes a number ofengaging clips 202, in use the sliding strap 200 snaps into place intothe engaging clips 202 and can only be removed therefrom using asubstantial force. This means that with any normal use the sliding strap200 will stay retained within the engaging clips 202. It will also beappreciated from FIG. 6 that a number of clips are so provided, in orderto allow pressure from different angles for different face shapes.

[0050] As shown in FIG. 8 the sliding strap includes a mid-section 204intended to reciprocate with the engaging clips 202, terminated at eachend by loops 206, 208 which attach to the headgear. The first loop 206is a full loop through which the headgear 108 is permanently attachedwith for example, a velcro strap. The loop 208 at the other end, is onlya partial loop 210 designed so that a strap or loop from the headgear108 can be easily slipped in or out of the open section 212 to alloweasy removal and attachment of the mask.

[0051] In a further alternative the sliding loop or strap could form acontinuous portion of the headgear. Other variations of the slidingconnection are possible, for example a clip or knob in the loop or strapcould slide withing slots in the mask body.

[0052] It will be appreciated that in all embodiments of the presentinvention the attachment from the headgear to the mask is designed toslide with the lowest possible friction while still ensuring adequatedirect force on the mask cushion to the user's face. As shown in FIG. 2the sliding connection 320 of the present invention allows the headgear322,324 to provide even force on both sides of the mask 326. This avoidsplacing a torque on the mask and consequent mask twisting, whichminimises mask leaks from the seal to the face 328.

[0053] Nasal Cannula

[0054] It will be appreciated that the present invention may be equallyapplied to any patient interface for delivery gases to a user.

[0055] Referring now particularly to FIGS. 9 and 10 we see that a nasalcannula 1100 is secured at its base to the back of a neonates head usingstrap 1150. The strap connects at the base of the neonates skull on theback of the neck. It connects to the cannula 1100 to by way of a slidingstrap 1152. This strap is secured by way of clips to the hard plasticbody 1138 allowing the securing strap 1150 substantial relative movementwith respect to the cannula 1100 as the neonate twists its head whileproviding adequate restraining force directly on the cannula 1100without any twisting of the cannula 1100. In one embodiment this isaccomplished by a plastic e.g. acetal sliding strap which engages intosliding clips on the outer face of the cannula. The Teflon strap isadjustably attached to the neck strap 150 to allow the tension to beadjusted to a comfortable level. Alternatively a sliding loop could beemployed.

[0056] Full Face Mask

[0057] Referring to FIGS. 11 to 13 and 18 a number of furtherembodiments are illustrated particularly relating to full face masks.Similarly to the preceding embodiments in FIG. 18 the mask 1200 isattached to headgear around the head of a patient with a sliding Teflonstrap 1202. The strap engages through a channel 1201 moulded into themask 1200.

[0058] Alternatively as seen in FIGS. 11 to 13 the mask 1200 is attachedto the headgear with a sliding loop 1204. The loop engages with theheadgear through Velcro loops 1206 and to the mask 1200 through clips1208.

[0059] Mouthpiece

[0060] Referring to FIGS. 14 to 16 a mouthpiece 1400 is shown employingembodiments of the present invention. The mouthpiece 1400 engages withsliding strap 1402 through a channel through the inlet 1404 of themouthpiece 1400. Again as with the preceding embodiments the strap 1402engages to the headgear through clips 1406 at each end. In FIG. 17 twostraps 1408, 1410 attach to the mouthpiece 1400 either side of the inlet1404 in a further alternative. The mouthpiece employed could otherwisebe as described in our European Patent Application No. 1163924 or othermouthpieces as would be contemplated by one skilled in the art.

[0061] It will be appreciated that numerous other interfaces for exampleE.T (endrotraceal) tubes might also be used in conjunction with thepresent invention.

1. A device for delivering a supply of gases to a user comprising orincluding: a patient interface, adapted to be in fluid communicationwith said supply of gases and said user in at least a correctorientation and position on said user, headgear adapted to attach to oraround the head of said user, and a sliding connection between saidheadgear and said patient interface.
 2. A device as claimed in claim 1wherein said patient interface is a nasal mask.
 3. A device as claimedin claim 2 wherein said nasal mask comprises or includes a body portionhaving an inlet receiving said supply of gases, and sealing meansattached to or integrated with said body portion said sealing meansadapted to seal against the facial contours of said user.
 4. A device asclaimed in claim 3 where said sliding connection adapted to allow saidheadgear substantial movement with respect to said nasal mask, whilestill providing compressive force on said sealing means to ensure saidsupply of gases is delivered to said user without significant leakage.5. A device as claimed in anyone of claims 1 to 4 wherein said headgearcomprises or includes a member engaged thereto, said engagement betweensaid headgear and said member adapted to allow temporary releasetherefrom.
 6. A device as claimed in claim 5 wherein said member iselongate having a first end and a second end, a first at least partialloop located at said first end and a second at least partial looplocated at said second end, whereby in use said headgear issubstantially permanently attached to said first loop and substantiallyattached but readily releasable from said second loop.
 7. A device asclaimed in claim 5 wherein said patient interface further comprises orincludes at least one restraining means on said body portion, in usesaid member is restrained in at least one axis by, but which can slideeasily within at least one other dimension, said restraining means andcan be easily disengaged therewith.
 8. A device as claimed in claim 1wherein said patient interface is a nasal cannula.
 9. A device asclaimed in claim 1 wherein said patient interface is a full face mask.10. A device as claimed in claim 1 wherein said patient interface is amouthpiece.
 11. A device as claimed in claim 1 wherein said patientinterface is an entrotracheal tube.
 12. A device as claimed in any oneof claims 8 to 11 wherein said headgear includes a low resistancesliding strap slidingly connected on, through, adjacent or with saidpatient interface.
 13. A device as claimed in claim 12 wherein saidsliding strap is moulded from polyacetal.
 14. A device as claimed in anyone of claims 8 to 11 wherein said headgear includes a low resistancesliding loop slidingly connected on, through, adjacent or with saidpatient interface.
 15. A device as claimed in claim 14 wherein saidsliding loop comprises a looped nylon filament.
 16. A nasal mask fordelivering gases to a user comprising or including: a body portionhaving an inlet, in use said inlet receiving a supply of gases, abuttingmeans engaged with said body portion for abutting against the facialcontours of said user, and engaging means for providing a slidingengagement with a means of securement to a user, and a compressive forceon said abutting means.
 17. A nasal mask as claimed in claim 16 whereinsaid engaging means comprises or includes restraining means, saidrestraining means adapted to in use accommodate an elongate member, saidrestraining means adapted to in use restrain said member in at least onedimension, but allow said member to slide easily within at least oneother dimension, and providing a compressive force on said abuttingmeans, said restraining means adapted to in use easily disengage withsaid member.
 18. In a CPAP system for delivering gases to a usercomprising or including a pressurised source of gases, a conduit influid communication with said pressurised source adapted to convey saidgases, a patient interface in fluid communication with said conduit inuse delivering said gases to said user, and headgear attaching saidinterface with said user the improvement comprising that said patientinterface adapted to sliding engage with said headgear.
 19. In a CPAPsystem as claimed in claim 18 the improvement further comprising thatsaid system further comprises a humidifier to variably humidify saidgases.
 20. A device for delivering a supply of gases to a usercomprising or including: a patient interface, adapted to be in fluidcommunication with said supply of gases and said user in at least acorrect orientation and position on said user, and headgear including atleast a partial loop adapted to pass across the face of said user.
 21. Adevice as claimed in claim 20 wherein said loop adapted to pass over andslidingly engage with said interface.
 22. A device as claimed in claim20 wherein said loop adapted to pass at least partially through andslidingly engage with said interface.
 23. A device as claimed in claim20 wherein said loop slides in use with respect to said headgear.